Heptafluoromonochlorocyclobutane and process of making same



Patented Sept. 9, 1041 H E P T A FLUOROMONOCHLOROGYCLOBU- TANE AND PROCESS OF MAKING SAME Paul L. Bar-rick, Wilmington, DeL, asslgnor to E. I. du Pont do Nemours 8: Company, Wilmington, DeL, a corporation of Delaware No Drawing. Application May 22, 1945,

3 Claims. (Cl. 280-648) This invention relates to a new composition of matter and more particularly to heptafluoro monochlorocyclobutane.

This application is a continuation in part of my copending application Serial No. 484,239, filed April 23, 1943.

This invention has as an object heptafiuoromonochlorocyclobutane. A further object resides in a method for preparing this compound. Additional objects will become apparent from an examination of the following description and claims.

These and other objects and advantages are accomplished according to the hereindescribed invention which comprises heating tetrafiuoroethylene, that has been rendered stable against polymerization on standing under pressure at 25 0., with chlor'otrifluoroethylene, that has also been rendered stable against polymerization on standing under pressure at 25 C.

The following example. in which proportionsare in parts by weight unless otherwise specified, is given for illustrative purposes and is not intended to place any restrictions on the hereindescribed invention.

Example A silver-lined high-pressure reactor was swept with nitrogen, closed, evacuated, chilled in a solid carbon dioxide/methanol mixture and charged with a-mixture of 47 parts of chlorotrifiuoroethylene and 34 parts of tetrafluoroethyl- .ene, which had been stabilized by reducing its iiuoroethylene employed in the above process should be stable against polymerization on standing under pressure at 25 C. The preparation of these stabilized polyfluoroethylenes, which is not a partoi this invention, can be accomplished by various means. One method consists in reducin the normally contained oxygen content (about 0.1% to 0.2% by volume) to not more than parts of oxygen in a million parts of the polyfluoroethylene. Another method for stabilizing these polyiiluoroethylenes against polymerization consists in adding polymerization inhibiting compounds. Compoundsof this kind are those containing thiol sulfur, examples of which are butyl mercaptan, hydrogen sulfide, and the like, and compounds containing amino nitrogen, for example, ammonia, diand tributylamine, and other amines. These methods are described in detail in U. S. Patents to Dietrich. et al.. No. 2,407,405, to Brumaker, 2,407,396 and to Hanford, No. 2,407,419, each 01 which was filed February 15, 1943, and issued September 10, 1946. Other compounds which are sometimes used as polymerization inhibitors include hydroquinone, "Terpene B hydrocarbon and alphapinene. The proportion of inhibitors may vary within relatively wide limits. Generally speaking, very valuable results are obtained with none or only relatively small amounts of inhibitors, corresponding to 0.0001% to 3% by weight of the material treated.

The proportion of reactants may vary somewhat but in general stoichiometric proportions are employed. The reaction between tetrafluoroethylene and chlorotrifluoroethylene is best carried out by heating under pressure in a closed system at a temperature of 100 C. or higher and preferably not above 300 C., and in the absence of a. polymerization catalyst. The reaction can, however, be effected at somewhat higher temperatures, 1. e., up to 550 C. but below the decomposition temperature of the reactants and the product.

The process can be operated continuously or intermittently. .The reaction and the separation or isolation of the product can be carried out simultaneously or in separate steps. The reaction can be carried out ina closed system as illustrated in the example or the reaction can be carried out in a vaporphase by mixing the vapors oi the reactants, andthen passing the mixture through a hotreaction tube. In gen- I eral, the reaction is carried out under autogenous 2. The process for obtaining heptafluoromonochlorocyclobutane, which comprises heating tetrafluoroethyiene with chlorotrifluoroethylene.

said tetrafluoroethylene and said chlorotrifluoroethylene. having been rendered stable against polymerization on standing under pressure at 25 0., said heating being eflected under pressure within the range of 0.1 to 1,000 atmospheres at a temperature within the range of from 100 C. to 300 C.

3. The process for obtaining heptafluoromonochlorocyclobutane. which comprises heating 4 chlorotrifluoroethylene with tetrafluoroethylene, each of which has been rendered stable against polymerization on standing under pressure at 25 C.. said heating being effected in a closed system under autogenous pressure at a. temperature from 100 C. to 550 C.

' PAUL L. BARRICK.

REFERENCES CITED The following references are of record in the file of this patent:

FOREIGN PATENTS Number Country Date 796,026 France Mar. 27, 1936 OTHER REFERENCES Swarts, Chemical Abstracts, vol. 30, cols. 4153- Ellis. Chemistry of Petroleum Derivatives, vol. np. 746-747.

Eglofl, Reactions of Pure Hydrocarbons, pp. 586-589. 

